Background: Rising human population has detrimental effects on quality of life and lead to increased cases of pollution and poverty. Modern forms of contraceptives also have severe side effects and result in high cases of unwanted pregnancies. As a result, several cases of illegal abortion, leading to serious health complications have been reported, and more than 30 million US dollars are used to treat post-abortion complications in Kenya annually. Herbal contraceptives offer Original Research Article
Lignin isolated from agricultural residues is a promising alternative for petroleum-based polymers as feedstocks in development of antimicrobial materials. A polymer blend based on silver nanoparticles and lignin–toluene diisocyanate film (AgNPs–Lg–TDIs) was generated from organosolv lignin and silver nanoparticles (AgNPs). Lignin was isolated from Parthenium hysterophorus using acidified methanol and used to synthesize lignin capped silver nanoparticles. Lignin–toluene diisocyanate film (Lg–TDI) was prepared by treating lignin (Lg) with toluene diisocyanate (TDI) followed by solvent casting to form films. Functional groups present and thermal properties of the films were evaluated using Fourier-transform infrared spectrophotometry (FT–IR), thermal gravimetry (TGA), and differential scanning calorimetry (DSC). Scanning electron microscopy (SEM), UV–visible spectrophotometry (UV–Vis), and Powder X-ray diffractometry (XRD) were used to assess the morphology, optical properties, and crystallinity of the films. Embedding AgNPs in the Lg–TDI films increased the thermal stability and the residual ash during thermal analysis, and the presence of powder diffraction peaks at 2θ = 20, 38, 44, 55, and 58⁰ in the films correspond to lignin and silver crystal planes (111). SEM micrographs of the films revealed the presence of AgNPs in the TDI matrix with variable sizes of between 50 to 250 nm. The doped films had a UV radiation cut-off at 400 nm as compared to that of undoped films, but they did not exhibit significant antimicrobial activity against selected microorganisms.
Aims: The purpose of the study was to determine the antioxidant activity, quantify total phenols and total flavonoids and characterize the secondary metabolites present in methanolic extracts of Chamaecrista hildebrandtii and Clerodendrum rotundifolium using liquid chromatography coupled to mass spectrometry (LC-MS).
Methodology: The total phenol and flavonoid contents were determined spectrophotometrically while the antioxidant activity was evaluated using the 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) free radical scavenging method. The secondary metabolites present in the methanolic leaves extracts were evaluated using LC-MS.
Results: The extracts of C. hildebrandtii showed a significantly higher antioxidant activity (IC50 = 8.7 mg/mL) compared to C. rotundifolium (IC50= 28.5 mg/mL). Both methanolic extracts of C. hildebrandtii and C. rotundifolium had common and different types of flavonoids such as quercetin, rutin, (+)-catechin 3-O-gallate and luteolin 6-C-glucoside among others that could be responsible for the observed antioxidant activity. The total phenolic content of C. hildebrandtii (1.33±0.07 mg/g tannic acid equivalents) was significantly higher than that of C. rotundifolium (0.25±0.00 mg/g tannic acid equivalents). However, there was no statistically significant difference (p>0.05) in total flavonoid content of C. hildebrandtii (2.69±0.33 mg/g catechin equivalents) and C. rotundifolium (2.36±0.16 mg/g catechin equivalents).
Conclusion: The results of the present study suggested that the good antioxidant activity exhibited by C. hildebrandtii may probably have been brought about by various secondary metabolites functioning in synergy.
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